Unplasticized polyvinyl chloride (PVC-U) casings represent a specialized class of thermoplastic tubing systems engineered for subsurface applications in deep foundation work, geotechnical investigation, and ground improvement operations. Composed of rigid PVC resin without plasticizers, PVC-U casings exhibit superior dimensional stability, chemical resistance, and durability compared to flexible alternatives. The material's inherent properties—including low weight, corrosion immunity, and ease of installation—make it an economical choice for borehole construction, casing advancement, and soil stabilization projects where long-term material integrity is critical. In deep foundation and geotechnical engineering, PVC-U casings serve multiple specialized functions. Primarily, they are deployed as borehole casings during foundation investigation, piling design validation, and soil profiling operations conducted by drilling rigs, exploration equipment, and CPT (Cone Penetration Testing) systems. The casings facilitate access to subsurface formations, allow groundwater monitoring installation, and support soil sampling campaigns. In ground improvement applications, PVC-U tubing acts as a conduit for jet grouting headers, stone columns, and soil-cement mixing systems. Additionally, PVC-U casings are integral to soil nailing, micropile installation, and vibration monitoring systems in deep excavation and retaining wall construction. PVC-U casings are supplied in modular form—typically 1–4 meter lengths with standardized connection systems (socket-and-spigot, threaded, or mechanical couplings)—facilitating rapid assembly and disassembly on site. Once delivered, casings are stored horizontally in protected areas to prevent UV degradation and mechanical damage. Field installation involves vertical or angled advancement using rotary drilling, percussion, or vibratory driving systems, depending on soil conditions and casing diameter. The lightweight nature of PVC-U (approximately 60% lighter than equivalent steel casings) reduces equipment requirements and accelerates deployment, particularly advantageous in remote or constrained project sites. Standard grades and diameters range from 63 mm to 500+ mm outer diameter, with wall thicknesses classified per EN 1401 (DN32 to DN630 designations) and ASTM F480 specifications. Common variants include solid-wall casings for standard boreholes, perforated casing for groundwater observation installations, and specialized profiles for jet grouting and micropile headers. Casing selection criteria encompass soil abrasiveness, groundwater chemistry, maximum drilling depth, and temperature range. Engineers evaluate borehole stability requirements, anticipated hydrostatic pressure, and chemical compatibility with grouting materials (cement, bentonite, polymers) to determine appropriate casing pressure class and material specifications. International standards governing PVC-U casing performance include EN 1401 (PVC pipes for drainage and sewerage), EN ISO 4435 (thermoplastics casing for boreholes), ASTM F480 (PVC pipe for well construction), and ISO 7481 (thermoplastics pipes). Compliance with these standards ensures predictable material behavior, dimensional consistency, and compatibility with standard drilling tooling. The material's resistance to acidic, alkaline, and saline groundwater environments, combined with chemical compatibility with common geotechnical grout systems and additives, provides enhanced longevity in challenging subsurface conditions—a fundamental requirement in deep foundation engineering where replacement access and remediation costs are prohibitive.
Unplasticized polyvinyl chloride (PVC-U) casings represent a specialized class of thermoplastic tubing systems engineered for subsurface applications in deep foundation work, geotechnical investigation, and ground improvement operations. Composed of rigid PVC resin without plasticizers, PVC-U casings exhibit superior dimensional stability, chemical resistance, and durability compared to flexible alternatives. The material's inherent properties—including low weight, corrosion immunity, and ease of installation—make it an economical choice for borehole construction, casing advancement, and soil stabilization projects where long-term material integrity is critical. In deep foundation and geotechnical engineering, PVC-U casings serve multiple specialized functions. Primarily, they are deployed as borehole casings during foundation investigation, piling design validation, and soil profiling operations conducted by drilling rigs, exploration equipment, and CPT (Cone Penetration Testing) systems. The casings facilitate access to subsurface formations, allow groundwater monitoring installation, and support soil sampling campaigns. In ground improvement applications, PVC-U tubing acts as a conduit for jet grouting headers, stone columns, and soil-cement mixing systems. Additionally, PVC-U casings are integral to soil nailing, micropile installation, and vibration monitoring systems in deep excavation and retaining wall construction. PVC-U casings are supplied in modular form—typically 1–4 meter lengths with standardized connection systems (socket-and-spigot, threaded, or mechanical couplings)—facilitating rapid assembly and disassembly on site. Once delivered, casings are stored horizontally in protected areas to prevent UV degradation and mechanical damage. Field installation involves vertical or angled advancement using rotary drilling, percussion, or vibratory driving systems, depending on soil conditions and casing diameter. The lightweight nature of PVC-U (approximately 60% lighter than equivalent steel casings) reduces equipment requirements and accelerates deployment, particularly advantageous in remote or constrained project sites. Standard grades and diameters range from 63 mm to 500+ mm outer diameter, with wall thicknesses classified per EN 1401 (DN32 to DN630 designations) and ASTM F480 specifications. Common variants include solid-wall casings for standard boreholes, perforated casing for groundwater observation installations, and specialized profiles for jet grouting and micropile headers. Casing selection criteria encompass soil abrasiveness, groundwater chemistry, maximum drilling depth, and temperature range. Engineers evaluate borehole stability requirements, anticipated hydrostatic pressure, and chemical compatibility with grouting materials (cement, bentonite, polymers) to determine appropriate casing pressure class and material specifications. International standards governing PVC-U casing performance include EN 1401 (PVC pipes for drainage and sewerage), EN ISO 4435 (thermoplastics casing for boreholes), ASTM F480 (PVC pipe for well construction), and ISO 7481 (thermoplastics pipes). Compliance with these standards ensures predictable material behavior, dimensional consistency, and compatibility with standard drilling tooling. The material's resistance to acidic, alkaline, and saline groundwater environments, combined with chemical compatibility with common geotechnical grout systems and additives, provides enhanced longevity in challenging subsurface conditions—a fundamental requirement in deep foundation engineering where replacement access and remediation costs are prohibitive.